Hull robot drive system

ABSTRACT

A hull robot includes a robot body, at least one drive module for maneuvering the robot about the hull, an on-board power source, and a motive subsystem for the drive module powered by the on-board power source. A plurality of permanent magnet elements are associated with the drive module and each are switchable between a non-shunted state when adjacent the hull and a shunted state when not adjacent the hull.

RELATED APPLICATIONS

This application is related to U.S. patent application Ser. No.12/313,643, filed on Nov. 21, 2008, and U.S. patent application Ser. No.12/583,346, filed on Aug. 19, 2009.

FIELD OF THE INVENTION

The subject invention relates to a hull robot typically configured toclean and/or inspect the hull of a vessel and, in particular, to a drivemodule for such a hull robot.

BACKGROUND OF THE INVENTION

Robots have been proposed to clean and inspect vessels and underwaterstructures. Such robots typically include a drive subsystem formaneuvering the robot about the vessel or structure hull. Some drivesubsystems include magnetic wheels or rollers. See U.S. Pat. Nos.5,628,271; 3,088,429; and 2,104,062. The magnetic wheels of the '271patent are stated to provide a holding power in excess of 2,000 pounds.The motor and drive train driving these wheels provides sufficienttorque to overcome the strong magnetic tractive force. For example, themotor is stated to be a 24 volt DC motor providing 400 RPM.

Other drive subsystems include rollers and some means of adhering therobot to the hull via suction. See U.S. Pat. Nos. 4,809,383; 6,102,145;and 6,053,267. Some use rollers or wheels and a magnet spaced from thehull. See U.S. Pat. Nos. 6,564,815; 3,922,991; and 3,777,834. U.S. Pat.No. 4,697,537 discloses an impeller driven by a motor urging the robotagainst the hull.

Magnetic tracks and tracks with magnetic shoes have also been proposed.See U.S. Pat. Nos. 3,960,229; 2,132,661; 4,690,092; and 4,890,567 alldisclosing electromagnets which may be selectively energized to controlthe drag force exerted by the magnets. U.S. Pat. No. 5,285,601,incorporated herein by this reference, discloses a blast cleaning devicewith two treads each including permanent magnets which continuouslyapply a tractive force.

BRIEF SUMMARY OF THE INVENTION

Some proposed hull cleaning robots are powered via a tether or cableconnected between the robot and a power source on board the vessel. Itmay be advantageous, however, for a hull robot to operate moreautonomously in which case the power source for the drive subsystem,cleaning brushes, and the like would be on-board the robot typically inthe form of a battery or battery pack. Drive subsystems includingelectromagnetics are not favored because electromagnets may require toomuch power to operate. High voltage powerful motors for the drivesubsystem are also not favored when battery power is used. At the sametime, if permanent magnets are used and they provide a fairly strongtractive force, it can be difficult to engineer a suitable drivesubsystem.

Co-pending U.S. patent application Ser. No. 12/313,643 filed Nov. 21,2008 by the assignee hereof proposes a robot with a battery pack chargedvia a turbine/generator subsystem driven by water flowing past the hullwhen the vessel is underway. In this manner, the hull robot cancontinuously clean and/or inspect the vessel hull. In such a hull robot,a permanent magnet type drive track is desired. But, as noted above,since the drive subsystem is battery powered, a mechanism to control thetractive force supplied by the permanent magnets is needed.

One embodiment features, in one aspect, a hull cleaning and/orinspection robot which is powered via fluid moving past the hull whilethe vessel is underway. A preferred drive module may include a pluralityof permanent magnet elements constrained by a tunnel body and switchablebetween a shunted state and a non-shunted state. In this way, themagnets are shunted as they reach the end of their travel along thetunnel body and remain shunted until they again engage the hull toconserve battery power. In their non-shunted state, the magnets providea sufficient tractive force to keep the hull robot on the hull of thevessel. In other embodiments, the drive module hereof may be used inconjunction with systems other than a hull cleaning and/or inspectionrobot.

An example of a hull robot includes a robot body, at least one drivemodule for maneuvering the robot about the hull, an on-board powersource, and a motive subsystem for the drive module powered by theon-board power source. A plurality of permanent magnet elements areassociated with the drive module and each are switchable between anon-shunted state when adjacent a hull and a shunted state when notadjacent the hull.

The motive subsystem may include at least one turbine powered by fluidmoving past the hull, a generator driven by the turbine for charging theon-board power source, and a motor powered by the on-board power sourcedriving the drive module. A typical on-board power source includes atleast one battery.

In one version, each magnet element includes a diametrically polarizedcylindrical magnet rotatably disposed in a housing. The preferredhousing includes non-magnetic material sandwiched between ferromagneticmaterial. Each magnet element may further include a switch attached tothe cylindrical magnet for rotating the cylindrical magnet in thehousing between the shunted state and the non-shunted state.

In one example, the drive module may also include a tunnel body and eachmagnet element may include a carriage which maneuvers with respect tothe tunnel body. The tunnel body may include opposing side tracks andthe carriage then includes spaced bearings riding in the side tracks ofthe tunnel body. The typical tunnel body may support a drive train andeach carriage is connected to the drive train. In one example, the drivetrain may include a chain about spaced sprockets engaging the chain.Each carriage typically includes at least one connector extending intothe chain.

There may also be spaced panels supporting the tunnel body. A pluralityof flexures typically may extend between each supporting panel and thetunnel body. In one example, the tunnel body is segmented and there isat least one flexure per segment. One or both panels may include aswitching feature such as a closed loop groove therein. The magnetswitch assemblies ride in the groove and the groove is configured toactivate switch assemblies to rotate the magnets at opposing ends of theclosed loop. Each magnet element may also include a protective covering.

Also featured is a drive module including a plurality of magnet elementseach having a housing with non-magnetic material sandwiched betweenferromagnetic material and a bore extending into the housing, a magnetrotatably disposed in the bore, and a switch assembly for rotating themagnet. A carriage for each magnet includes at least one bearing and aconnector. A tunnel body includes at least one track for the bearings ofthe carriages. A drive train for the tunnel body is attached to theconnectors of the carriages. At least one panel supports the tunnelbody. The panel typically includes means for actuating the switchassemblies such as a feature in the panel actuating the switchassemblies. The feature is configured to rotate the magnet at opposingends of the tunnel.

One drive module features a plurality of permanent magnet elements eachswitchable between a non-shunted state and a shunted state, a switchassembly for each magnet element rotating each permanent magnet elementto change the state thereof, a tunnel body constraining the permanentmagnet elements, and a drive train for driving the tunnel body withrespect to the permanent magnet elements. In one example, the meansdrive train includes spaced wheels rotatably supported by the tunnelassembly and a flexible member about the wheels connected to thepermanent magnet elements.

Thus, the subject invention in some embodiments, need not achieve allthe above objectives and the claims hereof should not be limited tostructures or methods capable of achieving these objectives.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Other objects, features and advantages will occur to those skilled inthe art from the following description of a preferred embodiment and theaccompanying drawings, in which:

FIG. 1 is a schematic three-dimensional view of the bottom of an exampleof a hull robot;

FIG. 2 is a schematic view showing the primary subsystems associatedwith the hull robot of FIG. 1;

FIG. 3 is a block diagram showing several of the subsystems associatedwith a typical hull cleaning robot;

FIG. 4 is a schematic three-dimensional partial front view showingseveral of the components associated with an example of a drive module;

FIG. 5 is a schematic three-dimensional front view showing one exampleof a switchable permanent magnetic element associated with a drivemodule;

FIG. 6 is a schematic cross-sectional side view showing the permanentmagnet element of FIG. 5 in its shunted state;

FIG. 7 is a schematic cross-sectional side view showing the permanentmagnet element of FIG. 5 in its non-shunted state;

FIG. 8 is a schematic three-dimensional side view of an example of atunnel body constraining the individual permanent magnet elements;

FIG. 9 is a schematic three-dimensional side view showing an example ofa portion of the mechanism which drives the tunnel body relative to thepermanent magnet elements;

FIG. 10 is a schematic three-dimensional side view of a segmented tunnelbody;

FIG. 11 is a schematic three-dimensional front view showing spaced sideplate members flexibly supporting the segmented tunnel body shown inFIG. 10;

FIG. 12 is a schematic three-dimensional front view showing in moredetail the flexure members of FIG. 11;

FIG. 13 is a schematic three-dimensional front view of the inside of oneof the panels of FIG. 11;

FIG. 14 is a schematic three-dimensional front view of the panels shownin FIG. 13 depicting how a feature in the panel acts as the switchactuator; and

FIG. 15 is a schematic three-dimensional bottom view showing an exampleincluding a plurality of drive modules in place on a hull robot.

DETAILED DESCRIPTION OF THE INVENTION

Aside from the preferred embodiment or embodiments disclosed below, thisinvention is capable of other embodiments and of being practiced orbeing carried out in various ways. Thus, it is to be understood that theinvention is not limited in its application to the details ofconstruction and the arrangements of components set forth in thefollowing description or illustrated in the drawings. If only oneembodiment is described herein, the claims hereof are not to be limitedto that embodiment. Moreover, the claims hereof are not to be readrestrictively unless there is clear and convincing evidence manifestinga certain exclusion, restriction, or disclaimer.

FIGS. 1-2 show one example of hull robot 10 with robot body 16supporting combined turbine/generator units 32 a and 32 b. The turbinesare responsive to fluid moving past the vessel hull when the vessel isunderway, e.g., the turbine intakes are behind screen 30 and areresponsive to fluid moving past the vessel hull. The turbines drive thegenerators which in turn charge battery pack 38. Electronic controlmodule 40 is powered by battery pack 38 as are the motors and otherpower devices on-board robot 10. Typically, one motor drives, forexample, gear 42 b which in turn drives gears 42 a and 42 c. In thisway, cleaning brushes 36 a-36 c are operated. Another motor is typicallyassociated with drive module 18 which both holds the robot on the hulland maneuvers the robot about the vessel hull. The motor system fordrive module 18 may vary in design. For example, the turbines coulddirectly drive module 18 (and/or brushes 36 a-36 c). Also, brushes 36a-36 c could be driven in different ways. There may also be more thanone drive module.

FIG. 3 illustrates an example including turbine subsystem 32 (includingone or more devices actuatable by fluid flowing past the hull) andgenerator 70 which recharges power source 40. One or more motors such asmotors 72 a and 72 b are powered by power source 40. Motor 72 a drivesdrive module 18 via drive train 74 a. The direction of travel of therobot can be reversed via electronic control subsystem 41 which isconfigured to reverse the direction of motor 72 a based on inputs, forexample, from navigation subsystem 78 and/or communication subsystem 80.Electronic controller 41 is also powered by power source 40. Similarly,motor 72 b drives cleaning subsystem 82 (e.g., one or more brushes asdescribed above) via drive train 74 b. Motor 72 b is also energized bypower source 40. In other embodiments, the one or more motors mayoperate on the basis of a power source other than electricity. Motorsare known, for example, that are fluid driven. The turbine subsystemthen, may pump fluid under pressure to the motors. If the cleaningsubsystem is passive, e.g., a pad and/or a squeegee, motor 72 b anddrive train 74 b would not be required. In other examples, the driveshafts of the turbines are mechanically linked to the cleaning brushesand/or drive module. Thus, the design of the motive subsystem for thedrive module may vary.

FIG. 4 schematically depicts certain components of a version of apreferred drive module. There are typically a plurality of permanentmagnet elements such as element 100. Switch assembly 102 switcheselement 100 between a shunted and a non-shunted state. Actuator 104actuates switch 102 typically between a shunted state when element 100is not adjacent the vessel hull and a non-shunted state when element 100is adjacent the vessel hull. Tunnel body 106 is configured to constrainthe movement of element 100 which typically includes some type ofcarriage 108. There are also some means to drive tunnel body 106 withrespect to permanent magnet element 100 as shown by arrow 110.

FIG. 5 shows a design where permanent magnet element 100 includesdiametrically polarized cylindrical magnet 120 rotatably disposed in abore of housing 122. Housing 122 includes non-magnetic material 124(e.g., aluminum, plastic, or the like) sandwiched between ferromagneticmaterial 126 a and 126 b (e.g., steel). Switch 102 is attached tocylindrical magnet 120 and rotates it as shown in FIG. 6-7. In FIG. 6,magnet 120 is shunted since the magnetic field flows from the northpole, outwardly through ferromagnetic material 126 a and 126 b, and tothe south pole. The attraction of magnet 120 to vessel hull 130 is thusminimized. Activating switch 102 rotates magnet 120 as shown in FIG. 7so each pole is proximate ferromagnetic material 126 a or 126 b. Asshown in figure, the south pole is in contact with ferromagneticmaterial 126 a and the north pole is in contact with ferromagneticmaterial 126 b. The magnetic field flows from the north pole of themagnet into body 126 b, to the ship's hull 130, to body 126 a, and thenback to the south pole of the magnet. In this non-shunted state, theattraction of magnet 120 to hull 130 is maximized.

Typically, switch 102 is activated to shunt magnet 120 as permanentmagnet element 100 reaches the end of its travel on the hull and switch102 is again activated to actuate magnet 120 as permanent magnet element100 again comes into contact with the hull. In this way, power usage isminimized and yet there is still a very strong tractive force providedto keep the robot on the hull. Power usage is minimized because power isnot wasted in removing the individual permanent magnet elements from thehull. Also, damage to the hull is minimized since the permanent magnetelements are not switched to their non-shorted states until they areactually in contact with the hull. Each permanent magnet element mayinclude a protective covering to also reduce damage to the vessel hull.The intent is to control the holding force exerted by the magnets but atthe same time use permanent magnets which consume no power unlikeelectromagnets.

FIG. 5 also shows carriage 108′ with spaced rotating bearings 140 a and140 b and connectors 142 a-142 d. Bearings 140 a and 140 b ride in sidetracks in tunnel body 106′, FIG. 8. In FIG. 8, oval shaped side track152 is shown.

FIG. 9 shows how tunnel body 106′ supports a drive train such as spacedsprocket wheels including wheel 160 (which may be driven by motor 72 aand drive train 74 a, FIG. 3). Chain 162 extends around the spacedsprocket wheels. Bearing 140 b of carriage 108′ of permanent magnetelement 100 a is constrained in track 152 of tunnel body 106′ andconnectors 142 c and 142 d extend into chain 162.

Since tunnel body 106′ is fixed to robot body 10, FIGS. 1-2 and sincepermanent magnet elements 100 b-100 e in their non-shunted states arestrongly attracted to vessel hull 130, chain 162 actually drives tunnelbody 106′ forward (and rearward) and thus the robot body is driven withrespect to the vessel hull via the rotation of chain 162 and aboutsprocket 160.

FIG. 9 also shows that permanent magnet element 100 a is shunted via theposition of switch 102. Permanent magnet element 100 x is either anelement first coming into position to be attracted to the hull 130 or itis leaving hull 130 depending on the direction of robot travel. Ifpermanent magnet element 100 x is just coming into position to beattracted to hull 130, it is switched from the shunted position shown toits non-shunted position once permanent magnet element 100 x occupiesthe position of permanent magnet element 100 b. If permanent magnetelement 100 x is just leaving hull 130, or is about to leave the hull,it is switched into a shunted state just after it occupies the positionof permanent magnet element 100 b.

FIG. 10 shows a segmented design for tunnel body 106″ to allow forarticulation of the tunnel body and track system to maximize the contactarea for each permanent magnet element in the presence ofnon-uniformities 170 a and 170 b on hull 130. In FIG. 11, spaced panels180 a and 180 b support tunnel body 106″ via flexures 182 a, 182 b, andthe like, FIGS. 11-12. Typically, there is at least one flexure for eachtunnel body segment as shown in FIG. 12. Side panels 180 a and 180 b areaffixed to the robot body or to a turret rotatably attached to the robotbody.

FIG. 11 also shows an actuation feature such as closed loop groove 184 aon the inside of panel 180 b. As shown in FIG. 13, these grooves in theside panels function to actuate the switches of the permanent magnetelements. At groove ends 186 a and 186 b there is a jog. If thedirection of travel of the hull robot is as shown by arrow 188 and thevessel hull is at the bottom of the figure, jog 186 b actuates thepermanent magnet element switches to shunt the permanent magnet elementsand at jog 186 a the switches are actuated again to return the permanentmagnet elements to their non-shunted configuration. FIG. 14 shows morecomplete switching assemblies 102 a-102 d and depicts how switch 102 ais in its shunted position but switch 102 b, via groove jog 186 a, hasbeen actuated to its non-shunted position. Similarly, jog 186 b turnsswitch 102 c to the shunted position for the remainder of its travelabout the front and top of panel 180 a corresponding to the front andtop of tunnel body 106′, FIG. 9.

FIG. 15 shows two complete drive modules 18 a and 18 b mounted to turret200 which may be rotatable with respect to the robot body. In this way,turret 200 can be rotated to keep the intakes of turbine/generatorassemblies 32 a and 32 b aligned with the direction of water flowingpast the vessel hull irrespective of the direction of travel of therobot about the vessel hull. See U.S. patent application Ser. No.12/583,346, filed Aug. 19, 2009.

In one preferred design, the tunnel body performs two functions: itconstrains the movement of the permanent magnet elements and also servesto house the drive mechanism (e.g., a chain about two sprockets)connected to the carriages of the permanent magnet elements. This designalso provides structural support against slack in the drive assembly.The side plates also serve two functions: they flexibly support thetunnel body and they include means for actuating the switches of thepermanent magnet elements. In the preferred design, the magneticelements are switched between their minimum tractive state and theirmaximum tractive state irrespective of the direction of travel of therobot. These are not limitations of the subject invention, however, asother designs are possible.

Other features associated with the typical hull robot are disclosed inthe patents cited in the Background section hereof and incorporatedherein by this reference. Also, U.S. patent application Ser. No.12/313,643 filed Nov. 21, 2008 by the assignee hereof disclosesadditional features which may be associated with a hull robot. The drivemodule disclosed herein, however, is not limited to use in connectionwith such a vessel hull robot. The drive module, for example, can beused on any ferromagnetic body including but not limited to vesselhulls, underwater structures, and the like. “Hull,” as used herein,then, broadly means a structure to be traversed.

Thus, although specific features of the invention are shown in somedrawings and not in others, this is for convenience only as each featuremay be combined with any or all of the other features in accordance withthe invention. The words “including”, “comprising”, “having”, and “with”as used herein are to be interpreted broadly and comprehensively and arenot limited to any physical interconnection. Moreover, any embodimentsdisclosed in the subject application are not to be taken as the onlypossible embodiments.

In addition, any amendment presented during the prosecution of thepatent application for this patent is not a disclaimer of any claimelement presented in the application as filed: those skilled in the artcannot reasonably be expected to draft a claim that would literallyencompass all possible equivalents, many equivalents will beunforeseeable at the time of the amendment and are beyond a fairinterpretation of what is to be surrendered (if anything), the rationaleunderlying the amendment may bear no more than a tangential relation tomany equivalents, and/or there are many other reasons the applicant cannot be expected to describe certain insubstantial substitutes for anyclaim element amended.

Other embodiments will occur to those skilled in the art and are withinthe following claims.

1. A hull robot comprising: a robot body; at least one drive module formaneuvering the robot about a hull, wherein the drive module includes atunnel body; an on-board power source; a motive subsystem for the drivemodule powered by the on-board power source; and a plurality ofpermanent magnet elements associated with the drive module eachswitchable between a non-shunted state when adjacent the hull and ashunted state when not adjacent the hull, wherein each magnet elementincludes a carriage which maneuvers with respect to the tunnel body. 2.The hull robot of claim 1 in which the motive subsystem includes atleast one turbine powered by fluid moving past the hull, a generatordriven by the turbine for charging the on-board power source, and amotor powered by the on-board power source driving the drive module. 3.The hull robot of claim 1 in which the on-board power source includes atleast one battery.
 4. The hull robot of claim 1 in which each magnetelement includes a diametrically polarized cylindrical magnet rotatablydisposed in a housing.
 5. The hull robot of claim 4 in which the housingincludes non-magnetic material sandwiched between ferromagneticmaterial.
 6. The hull robot of claim 4 in which each magnet elementfurther includes a switch attached to the cylindrical magnet forrotating the cylindrical magnet in the housing between the shunted stateand the non-shunted state.
 7. The hull robot of claim 1 in which thetunnel body includes opposing side tracks and the carriage includesspaced bearings riding in the side tracks of the tunnel body.
 8. Thehull robot of claim 1 in which the tunnel body supports a drive train.9. The hull robot of claim 8 in which each carriage is connected to thedrive train.
 10. The hull robot of claim 9 in which the drive trainincludes a chain about spaced sprockets engaging the chain.
 11. The hullrobot of claim 10 in which each carriage includes at least one connectorextending into the chain.
 12. The hull robot of claim 1 furtherincluding spaced panels supporting the tunnel body.
 13. The hull robotof claim 12 further including a plurality of flexures extending betweeneach supporting panel and the tunnel body.
 14. The hull robot of claim13 in which the tunnel body is segmented and there is at least oneflexure per segment.
 15. The hull robot of claim 12 in which each magnetelement includes a rotatable magnet and a switch assembly attachedthereto.
 16. The hull robot of claim 15 in which at least one said panelincludes a closed loop grove therein, the switch assembly rides in thegroove, and the groove is configured to activate the switch assembliesto rotate the magnets at opposing ends of the closed loop.
 17. The hullrobot of claim 1 in which each magnet element includes a protectivecovering.
 18. A drive module comprising: a plurality of magnet elementseach including: a housing with non-magnetic material sandwiched betweenferromagnetic material and a bore extending into the housing, a magnetrotatably disposed in the bore, and a switch assembly for rotating themagnet; a carriage for each magnet including at least one bearing and aconnector; a tunnel body including at least one track for the bearingsof the carriages; a drive train for the tunnel body attached to theconnectors of the carriages; and at least one support for the tunnelbody.
 19. The drive module of claim 18 in which the support includesmeans for actuating the switch assemblies.
 20. The drive module of claim19 in which the means for actuating includes a feature in the supportactuating the switch assemblies, the feature configured to rotate themagnet at opposing ends of the tunnel.
 21. A drive module comprising: aplurality of permanent magnet elements each switchable between anon-shunted state and a shunted state; a switch assembly for each magnetelement rotating each permanent magnet element to change the statethereof; a tunnel body constraining the permanent magnet elements; and adrive train for driving the tunnel body with respect to the permanentmagnet elements.
 22. The drive module of claim 21 in which eachpermanent magnet element includes a diametrically polarized cylindricalmagnet rotatably disposed in a housing including non-magnetic materialsandwiched between ferromagnetic material.
 23. The drive module of claim22 in which each said switch assembly rotates the diametricallypolarized cylindrical magnet between a shunted state and a non-shuntedstate.
 24. The drive module of claim 21 in which the drive trainincludes spaced wheels rotatably supported by the tunnel assembly and aflexible member about the wheels connected to the permanent magnetelements.
 25. A hull robot comprising: a robot body; at least one drivemodule for maneuvering the robot about a hull; an on-board power source;a motive subsystem for the drive module powered by the on-board powersource; and a plurality of permanent magnet elements associated with thedrive module, each of the magnet elements including a diametricallypolarized cylindrical magnet rotatably disposed in a housing, and aswitch attached to the cylindrical magnet for rotating the cylindricalmagnet in the housing between a non-shunted state when adjacent the hulland a shunted state when not adjacent the hull.